My wife's car sometimes gets a burnt motor oil smell through the vents. It's a 2001 Sable, with the duratec, we bought used with about 12,000 miles on it in early 2005, and it has over 46,000 now.

Research has turned up possible causes. I started with what I thought would be the simplest, the PCV valve. Well, it wasn't cause, but I replaced the valve anyway since it turned out to be a PITA.

Which leaves the valve covers and oil pan gasket. Both have oil and grime around them. On the oil pan, it could easily be from the unavoidable spill when removing the oil filter. There have been oil seep stains around the valve covers for years. Perhaps a leak finally reached a spot where it can burn, or I just attributed it to spills from the filter.

The valve cover is the most likely culprit. I just dread replacing the gaskets. Mostly because of everything that has to be removed to get to that rear cover.

I took a look at some stop leak addatives. The ones that work by reconditioning and swelling the gaskets, how effective are they? Any potential problems with their use? If I have to, I'll take the plung and do my first valve cover job, but it would be nice if I could avoid putting out $50 for a gasket set.

The valve cover gaskets shouldn't cost $50...you should be able to get them for $20. I'd probably start with cleaning around them and then seeing where oil shows up first. You might be able to ignore the rear one and just do the easier front one.

If it was my car, I'd replace the valve cover gaskets. The stop leak would do very little to help a valve cover leak and it could weaken the other seals that are even harder to get to (like the rear crankshaft seal).